1. Field of the Invention
This invention relates to keypad and keyboard systems for data entry or device control and more particularly, to a directionally-mapped, keyed alpha-numeric data input/output system.
2. Background
On the present day conventional telephone keypad, there are ten numbered keys, an asterisk key and a pound sign key. The letters of the alphabet are listed in groups of three on eight of the number keys. Entering numerals is performed by simply depressing the indicated keys in turn. However, for entering any given letter (alpha) a special series of key strokes is required, and this method is not generally accepted or understood by the public. In telecommunication applications such as voice mail directory search or in a stock purchase using an electronic broker, a unique interpretation of alpha data codes is often necessary. As a result, errors in alpha data entry, using the conventional keypad, are a common and frustrating occurrence. The above prompts frequent requests for a simple, relatively error free method of alpha data and numeric data entry.
There have been many devices invented and available which purport to solve the problem posed by alpha-numeric data entry in a conventional key array, but none have been accepted by the public or manufacturers to date. This has been expressed as being primarily because of their difficulty in use and/or manufacturing.
Keyboards for computers and control panels typically have many keys, with some keys having two possible functions. The resulting keyboard size is acceptable for desktop computers, but not for space constrained computers such as laptops or various small, portable control panels. The current solution has been to make the keys very small in size and to require depressing several keys in correct sequence for a given command entry. For a user having large fingers, a small key surface and small separation between keys is unsatisfactory and invites error. Thus, key size and the number of keys needed, determine the size of the board or keypad.
For the manufacturers of remote controllers, calculators, games, mobile phones and similar electronic communication equipment, the space required for adequate data entry with conventional keys presents a continuing problem due to space limitations, and hinders desirable miniaturization of the device.
There exist many patents that address the alpha-numeric keypad problem. However, none disclose a system for keypad/keyboard data entry that provides for error-free data without complexity, or allows for practical miniaturization of a keypad/keyboard while permitting any desired number of distinct, single key data entries in a simple "hands on" format.
In many of the prior art patents such as those of Hashimoto, U.S. Pat. No. 4,918,721 and Wen, U.S. Pat. No. 4,825,464, the alpha-numeric keypad data entry problem was solved, but the solution proved to be too elaborate and cumbersome for general use. However, the use of keypads with multi-directional keys is taught by a number of patents, and this is an approach that promises a possibility of keyboard miniaturization. Among these patents is a disclosure by Lin et al in U.S. Pat. No. 5,528,235. Lin et al disclose a multi-status data entry key and a keyboard that is capable of a one-to-one correspondence between each key status and a pre-assigned signal or state. This is done by using a key having five facets and mounting it on a spring so that it can rock in four orthogonal directions and downwards. Thus each "key" acts as five keys; each facet direction push entering a different piece of data. No description or claim is given by Lin et al for the system required to convert and transmit this input data in usable form.
Unfortunately, the Lin et al invention and similar devices have not succeeded in the industrial market for telephonic communication or remote controllers and similar equipment. The reasons given by industry sources for failure to adopt these invention devices, include the likelihood of user finger tactile errors in data entry using multi-faceted keys such as described by Lin et al as well as an expensive complexity in manufacturing the device, particularly the keys.
In view of the foregoing, it is clear that there remains a need for a simple, relatively error-free alpha-numeric data entry system for telecommunication equipment, as well as for space-constrained computers, miniaturized controllers and the like.